Review: Mammut Crag IN Jacket

Coming in a disrespectful third behind fossil fuels and agriculture, garments and textiles produce about 10 percent of the annual global carbon footprint. While it’s easy to point fingers at fast fashion, the impact caused by the outdoor industry is not insignificant. However, there has been a collective push from within to find better, greener, and more sustainable ways to manufacture.

Serious outdoor brands are now making high-performance waterproof jackets without the use of PFAS “forever” chemicals, while initiatives such as NetPlus transform rescued fishing nets into usable materials, and the Single Use Plastics Project help to find new ways with plastic recycling.

PrimaLoft has been producing synthetic insulation, made from recycled plastic bottles, for years, but with Loopinsulation, Swiss climbing brand Mammut is taking sustainable warmth one step further by turning old climbing ropes into high-performance insulation.

Developed in conjunction with Austrian firm Teufelberger—which has been making climbing ropes for Mammut since 2016—the closed-loop insulation manufacturing process used to create its first collection of insulated jackets, starts with a mountain of industrial rope offcuts. These randomly sized scraps of polyester would have previously been discarded, but now they’re untangled and sorted into individual strands. These strands are then brushed together and mixed with recycled plastic without the need for any binding chemicals. The result is a roll of highly insulating, completely recycled wadding.

The development of Loopinsulation started in 2018, when Mammut discovered that 13 percent of the company’s CO₂ emissions came from rope manufacturing. So far the brand has recycled 12-tons of rope scraps, which doesn’t seem like a lot, but the fact it has pushed the button and brought products to market should be applauded.

The outer fabric has a 20-denier thickness and is a comparable weight to other jackets at this price.

Photograph: Chris Haslam